Daylight developing of photographic plates and films



Nov. 24, 1925' G. D. RODRIGUEZ DAYLIGHT DEVELOPING 0F PHOTOGRAPHIC PLATES AND FILMS Filed Oct. 29,- 1921 wmvsss mmvnm Gas-60pm UELHN/FZ IG M W W a i ATTORNEYS Patented Nov. 24, 1925.

UNITED "STATES GBEGORIO DELFIN RODRIGUEZfOF LEbiN, NICARAGUA.

DAYLIGHT DEVELOPING OF PHOT OGRAPHIC PLATES AND FILMS.

Application filed October 29, 1921. Serial No. 511,259.

To all whom it may concern:

Be it known. that I, GREGORIO DELFIN RODRIGUEZ, a citizen of the Republic of Nicaragua, and a resident of Leon, Nicaragua, Central'America, have invented new and useful Improvements in Daylight Developing of Photographic Plates and Films. of which. the following is a full, clear, and exact description.

The invention relates to photography, and its object is to provide certain new and useful improvements in daylight developing of photographic plates and films whereby the developing process can be readily carried out in the field in broad'daylight without the use of a stationary dark room.

The desired result is produced by .a method consisting essentially in transferring an exposed sensitized plate or film under exclusion oflight from a plate holder or a camera intoan envelope made of inactinic material, and then placing this filled envelope into a liquid developer contained in a tray and rendered opaque by the use of india ink or other inert dark color, or similar substance.

In order to carry this method into efi'ect use is made of the paraphernalia shown in the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in both views.

, Figure 1 is a sectional side elevation of a portable dark room illustrating the step of transferring an exposed sensitized plate from a plate holder into an opaque envelope: and

' Figure 2 is a sectional side elevation of a developing tray with the filled envelope submerged in the liquid developer rendered opaque.

The method is carried out in detail as follows: The usual plate holder 10 containing an exposed sensitized plate 1 1 is placed in a portable dark room 12 of usual construction provided at the bottom with a door 13,

' at the sides with sleeves 14, and at the top with a colored window 15 to permit the user to view the transferring of the exposed sen sitized plate 11 from the plate holder 10 into an envelope16 made of lnactinic material. In ractice, the plate holder-10 with the exposed sensitized plate 11 therein and the envelope 16 are placed in the portable dark room 12 by we. of the door 13 after which the latter is c osed, and then the operator inserts the two arms through the sleeves 14, as indicated in Figure 1. The operator next withdraws the slide 17 from the plate holder 10 and transfers the exposed sensitized plate 11 from the plate holder 10 into the envelope 16. When this has been done the operator withdraws the arms from the sleeves 14, opens the door 13 and removes the filled envelope 16 from the dark room 12. The envelope 16 with the exposed sensitized plate 11 therein is next placed in a developing tray 20 containing a llqllld developer 21 rendered opaque by the addition of india ink, or other inert. dark color, or a similar substance, which does not affect the developing action of the liquid developer 21. The tray 20 is manipulated in the usual manner to cause the developlng liquid 21 to enter the open mouth of the envelop 16 to act on the sensitized surface of the plate 11 with a view to develop the same. After the developing of the plate 11 has been completed it is thoroughly washed in another tray containing clear .the opaque envelope 16 during the developing process. Thus two safety means are provided to prevent the plate or film from becoming light-struck during the developing operation.

Having thus described my invention. I claim as new and desire to secure by Letters Patent I 1. The herein described method for daylight developin of exposed sensitized plates and films, which consists in transferring the exposed sensitized plate or film under the exclusion of light into an envelope of inaetinic material. and then immersing the envelope with the plate or film therein in a developer containing a black inert substance to render the developer opaque.

2. A developer for photographic plates and films containing a black inert substance to render the developer opaque.

3..A developer for photographic plates and films containing india ink, whereby the developer'is rendered opaque.

GREGORIO DELFIN RODRIGUEZ. 

